RucioFileCatalogClient.setMetadata returns empty result on success

[maxnoe]

The operations works, but the Successfull dict is empty:

In [8]: help(fc.setMetadata)
In [17]: from rucio.client.client import Client

In [18]: from DIRAC.Resources.Catalog.RucioFileCatalogClient import RucioFileCatalogClient

In [19]: fc = RucioFileCatalogClient()

In [20]: c = Client()

In [21]: fc.setMetadata('/ctao.dpps.test/t_20251008_091736_f4f2/test.dat', {'test-meta3': 'bar'})
Out[21]: {'OK': True, 'Value': {'Successful': {}, 'Failed': {}}}

In [22]: c.get_metadata(scope="t_20251008_091736_f4f2", name='/ctao.dpps.test/t_20251008_091736_f4f2/test.dat', plugin='JSON')["test-meta3"]
Out[22]: 'bar'

[maxnoe]

cc @cserf @gillardoLapp